Inductive charging enables a device to receive power without using conductive electrical contacts, such as those found in a plug. Inductive charging uses an electromagnetic field to transfer energy between two devices. Typically, a primary induction coil is used to create an electromagnetic field from within a charging device, and the electromagnetic field induces a secondary induction coil within a receiving device to generate a current.
The use of inductive coils for charging devices presents certain advantages, such as the convenience of charging without having to connect male or female connectors. In some situations, it may be beneficial to use inductive coils to charge a device instead of having exposed electrical contacts. However, due to the characteristics of the inductive coils, certain disadvantages exist. For example, when a conductor, such as a coil, is exposed to a changing magnetic field, a circulating flow of electrons can be caused within the body of the conductor. This circulating flow of electrons, called eddy currents, can generate unwanted heat and can cause energy loss in the inductive system. Other problems associated with the use of inductive coils can occur as a result of hysteresis.
As devices increasingly become smaller in size, the inductive coils that are included in such devices are also being designed to be smaller in size. However, despite the inductive coil being very small in size, the disadvantages due to eddy current loss and hysteresis loss still remain.